#ifndef GTL_NOISE_HEADER_GUARD
#define GTL_NOISE_HEADER_GUARD

#include "gtlMath.h"

namespace GTL
{

  namespace Noise
  {
    template <typename T>
    T Perlin_Fade(const T& t)
    {
      return t * t * t * (t * (t * (T)6 - (T)15) + (T)10);
    }

    template <typename T>
    T Perlin_Lerp(const T& t, const T& a, const T& b)
    {
      return a + t * (b - a);
      //T f = (1 - GTL::Math::Cosine(t * 3.1415927)) * .5; return a*(1-f)+b*f;
    }

    template <typename T>
    T Perlin_Grad1(int hash, const T& x)
    {
      int h = hash & 15;
      T u = h<8 ? x : (T)0, v = h<4 ? (T)0 : h==12||h==14 ? x : (T)0;
      return ((h&1) == 0 ? u : -u) + ((h&2) == 0 ? v : -v);
    }

    template <typename T>
    T Perlin_Grad2(int hash, const T& x, const T& y)
    {
      int h = hash & 15;
      T u = h<8 ? x : y, v = h<4 ? y : h==12||h==14 ? x : (T)0;
      return ((h&1) == 0 ? u : -u) + ((h&2) == 0 ? v : -v);
    }

    template <typename T>
    T Perlin_Grad3(int hash, const T& x, const T& y, const T& z)
    {
      int h = hash & 15;
      T u = h<8 ? x : y, v = h<4 ? y : h==12||h==14 ? x : z;
      return ((h&1) == 0 ? u : -u) + ((h&2) == 0 ? v : -v);
    }

    static const int Perlin_P[] = {
      151,160,137,91,90,15,
      131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23,
      190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33,
      88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,134,139,48,27,166,
      77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244,
      102,143,54, 65,25,63,161, 1,216,80,73,209,76,132,187,208, 89,18,169,200,196,
      135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,250,124,123,
      5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42,
      223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167, 43,172,9,
      129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,97,228,
      251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,107,
      49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254,
      138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180
      ,
      151,160,137,91,90,15,
      131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23,
      190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33,
      88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,134,139,48,27,166,
      77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244,
      102,143,54, 65,25,63,161, 1,216,80,73,209,76,132,187,208, 89,18,169,200,196,
      135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,250,124,123,
      5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42,
      223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167, 43,172,9,
      129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,97,228,
      251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,107,
      49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254,
      138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180
    };

    template <typename T>
    T PerlinNoise1(T x)
    {
      // Find unit cube that contains point
      int X = (int)x & 255;
      // Find relative x,y,z of point in cube
      x -= Math::Floor(x);
      // Compute Perlin_Fade curves for each x,y,z
      T u = Perlin_Fade(x);
      // Hash coordinates of the 8 cube corners
      int A = Perlin_P[X  ], AA = Perlin_P[A];
      int B = Perlin_P[X+1], BA = Perlin_P[B];

      // and add blended results from 8 curners of cube
      return Perlin_Lerp(u,
        Perlin_Grad1(Perlin_P[AA  ], x   ),
        Perlin_Grad1(Perlin_P[BA  ], x-1 ));
    }

    template <typename T>
    T PerlinNoise2(T x, T y)
    {
      // Find unit cube that contains point
      int X = (int)x & 255;
      int Y = (int)y & 255;
      // Find relative x,y,z of point in cube
      x -= Math::Floor(x);
      y -= Math::Floor(y);
      // Compute Perlin_Fade curves for each x,y,z
      T u = Perlin_Fade(x);
      T v = Perlin_Fade(y);
      // Hash coordinates of the 8 cube corners
      int A = Perlin_P[X  ]+Y, AA = Perlin_P[A], AB = Perlin_P[A+1];
      int B = Perlin_P[X+1]+Y, BA = Perlin_P[B], BB = Perlin_P[B+1];

      // and add blended results from 8 curners of cube
      return Perlin_Lerp(v,
        Perlin_Lerp(u,
          Perlin_Grad2(Perlin_P[AA  ], x  , y   ),
          Perlin_Grad2(Perlin_P[BA  ], x-1, y   )),
        Perlin_Lerp(u,
          Perlin_Grad2(Perlin_P[AB  ], x  , y-1 ),
          Perlin_Grad2(Perlin_P[BB  ], x-1, y-1 )));
    }

    template <typename T>
    T PerlinNoise3(T x, T y, T z)
    {
      // Find unit cube that contains point
      int X = (int)x & 255;
      int Y = (int)y & 255;
      int Z = (int)z & 255;
      // Find relative x,y,z of point in cube
      x -= Math::Floor(x);
      y -= Math::Floor(y);
      z -= Math::Floor(z);
      // Compute Perlin_Fade curves for each x,y,z
      T u = Perlin_Fade(x);
      T v = Perlin_Fade(y);
      T w = Perlin_Fade(z);
      // Hash coordinates of the 8 cube corners
      int A = Perlin_P[X  ]+Y, AA = Perlin_P[A]+Z, AB = Perlin_P[A+1]+Z;
      int B = Perlin_P[X+1]+Y, BA = Perlin_P[B]+Z, BB = Perlin_P[B+1]+Z;

      // and add blended results from 8 curners of cube
      return Perlin_Lerp(w,
        Perlin_Lerp(v,
          Perlin_Lerp(u,
            Perlin_Grad3(Perlin_P[AA  ], x  , y  , z   ),
            Perlin_Grad3(Perlin_P[BA  ], x-1, y  , z   )),
          Perlin_Lerp(u,
            Perlin_Grad3(Perlin_P[AB  ], x  , y-1, z   ),
            Perlin_Grad3(Perlin_P[BB  ], x-1, y-1, z   ))),
        Perlin_Lerp(v,
          Perlin_Lerp(u,
            Perlin_Grad3(Perlin_P[AA+1], x  , y  , z-1 ),
            Perlin_Grad3(Perlin_P[BA+1], x-1, y  , z-1 )),
          Perlin_Lerp(u,
            Perlin_Grad3(Perlin_P[AB+1], x  , y-1, z-1 ),
            Perlin_Grad3(Perlin_P[BB+1], x-1, y-1, z-1 ))));
    }

    template <typename T>
    T BrownianNoise1(const T& x, uint32_t i, const T& Persistence)
    {
      T R = (T)0;
      T Frequency = (T)1, Amplitude = (T)1;
      for (uint32_t j = 0; j < i; j++)
      {
        R += PerlinNoise1(x * Frequency) * Amplitude;
        Frequency *= (T)2;
        Amplitude *= Persistence;
      }
      return R;
    }

    template <typename T>
    T BrownianNoise2(const T& x, const T& y, uint32_t i, const T& Persistence)
    {
      T R = (T)0;
      T Frequency = (T)1, Amplitude = (T)1;
      for (uint32_t j = 0; j < i; j++)
      {
        R += PerlinNoise2(x * Frequency, y * Frequency) * Amplitude;
        Frequency *= (T)2;
        Amplitude *= Persistence;
      }
      return R;
    }

    template <typename T>
    T BrownianNoise3(const T& x, const T& y, const T& z, uint32_t i, const T& Persistence)
    {
      T R = (T)0;
      T Frequency = (T)1, Amplitude = (T)1;
      for (uint32_t j = 0; j < i; j++)
      {
        R += PerlinNoise3(x * Frequency, y * Frequency, z * Frequency) * Amplitude;
        Frequency *= (T)2;
        Amplitude *= Persistence;
      }
      return R;
    }
  }
}
#endif